Epoxy acid based biodegradable set retarder for a cement composition

ABSTRACT

Compositions and methods according to the invention are directed to a cement composition for use in a subterranean formation. The cement composition comprises: (A) cement; (B) water; and (C) a polymer, wherein the polymer: (i) comprises a monomer or monomers selected from the group consisting of epoxysuccinic acid, a substituted epoxysuccinic acid, and an alkali metal salt, alkaline earth metal salt, or ammonium salt of any of the foregoing, and any combination of any of the foregoing; (ii) has the following characteristics: (a) is water soluble; and (b) is biodegradable; and (iii) is capable of providing: (a) a thickening time of at least 2 hours for a test composition at a temperature of 190° F. and a pressure of 5,160 psi; and (b) an initial setting time of less than 24 hours for the test composition at a temperature of 217° F. and a pressure of 3,000 psi, wherein the test composition consists of 860 grams of Class-H Portland cement, 325 grams of deionized water, and 0.4% by weight of the cement of the polymer. The method comprises the steps of: (A) introducing the cement composition into the subterranean formation; and (B) allowing the cement composition to set after introduction into the subterranean formation.

FIELD OF THE INVENTION

The invention is directed to a cement composition for use in asubterranean formation and a method for cementing a subterraneanformation. In certain embodiments, the subterranean formation ispenetrated by an oil or gas well.

SUMMARY

According to an embodiment, a cement composition comprises: (A) cement;(B) water; and (C) a polymer, wherein the polymer: (i) comprises amonomer or monomers selected from the group consisting of epoxysuccinicacid, a substituted epoxysuccinic acid, and an alkali metal salt,alkaline earth metal salt, or ammonium salt of any of the foregoing, andany combination of any of the foregoing; (ii) has the followingcharacteristics: (a) is water soluble; and (b) is biodegradable; and(iii) is capable of providing: (a) a thickening time of at least 2 hoursfor a test composition at a temperature of 190° F. and a pressure of5,160 psi; and (b) an initial setting time of less than 24 hours for thetest composition at a temperature of 217° F. and a pressure of 3,000psi, wherein the test composition consists of 860 grams of Class-HPortland cement, 325 grams of deionized water, and 0.4% by weight of thecement of the polymer.

According to another embodiment, a method for cementing in asubterranean formation comprises the steps of: (A) introducing thecement composition into the subterranean formation; and (B) allowing thecement composition to set after introduction into the subterraneanformation.

BRIEF DESCRIPTION OF THE DRAWING

The features and advantages of the inventions will be more readilyappreciated when considered in conjunction with the accompanyingdrawing. The accompanying drawing is incorporated into the specificationto help illustrate examples of certain embodiments. The drawing is notto be construed as limiting the invention.

The experiments for the data contained in the drawing were performed ona cement composition, having a density of 16.4 pounds per gallon (ppg),containing: 5.48 gallons of deionized water; Class-H cement; SSA-2™strength stabilizer at a concentration of 35% by weight of the cement(bwc); HALAD®344 fluid loss additive at a concentration of 0.5% bwc; andpolyepoxysuccinic acid (PESA). The drawing includes the followingfigures:

FIG. 1 is a graph of thickening time in minutes (min) versus temperaturein Fahrenheit (° F.) for the cement composition at a pressure of 10,200psi with PESA at a concentration of 0.4% bwc.

FIG. 2 is a graph of thickening time in minutes (min) versusconcentration of PESA for the cement composition at a temperature of217° F. and a pressure of 10,200 psi.

FIG. 3 is a graph of temperature (° F.) and consistency (Bc) versus time(hr:min) for the cement composition at a pressure of 10,200 psi withPESA at a concentration of 0.4% bwc. The upper lines (beginning at timezero) indicate temperature and the lower line (beginning at time zero)indicates consistency of the cement composition.

FIG. 4 is a graph of temperature (° F.) and consistency (Bc) versus time(hr:min) for the cement composition at a pressure of 10,200 psiadditionally containing sodium chloride (NaCl) at a concentration of 35%by weight of the water and PESA at a concentration of 0.4% bwc. Theupper lines (beginning at time zero) indicate temperature and the lowerline (beginning at time zero) indicates consistency of the cementcomposition.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the words “comprise,” “have,” “include,” and allgrammatical variations thereof are each intended to have an open,non-limiting meaning that does not exclude additional elements or steps.

As used herein, the words “consisting essentially of” and allgrammatical variations thereof are intended to limit the scope of aclaim to the specified materials or steps and those that do notmaterially affect the basic and novel characteristic(s) of the claimedinvention.

Oil and gas hydrocarbons are naturally occurring in some subterraneanformations. A subterranean formation containing oil or gas is sometimesreferred to as a reservoir. A reservoir may be located under land or offshore. Reservoirs are typically located in the range of a few hundredfeet (shallow reservoirs) to a few tens of thousands of feet (ultra-deepreservoirs). In order to produce oil or gas, a well is drilled into asubterranean formation.

As used herein, a “well” includes at least one wellbore drilled into asubterranean formation, which may be a reservoir or adjacent to areservoir. A wellbore can have vertical and horizontal portions, and itcan be straight, curved, or branched. As used herein, the term“wellbore” refers to a wellbore itself, including any uncased, open-holeportion of the wellbore. A near-wellbore region is the subterraneanmaterial and rock of the subterranean formation surrounding thewellbore. As used herein, a “well” also includes the near-wellboreregion. The near-wellbore region is considered to be the region withinabout 100 feet of the wellbore. As used herein, “into a well” means andincludes into any portion of the well, including into the wellbore orinto the near-wellbore region via the wellbore.

As used herein, a “fluid” is a substance having a continuous phase andthat tends to flow and to conform to the outline of its container whenthe substance is tested at a temperature of 71° F. and a pressure of oneatmosphere. An example of a fluid is a liquid or gas. As used herein, a“fluid” can have more than one distinct phase. For example, a “fluid”can be or include a slurry, which is a suspension of solid particles ina continuous liquid phase; it can be or include an emulsion, which is asuspension of two or more immiscible liquids where droplets of at leastone liquid phase are dispersed in a continuous liquid phase of another;or it can be or include a foam, which is a suspension or dispersion ofgas bubbles in a continuous liquid phase.

In order to produce oil or gas, a wellbore is drilled into or near asubterranean formation. The wellbore may be an open hole or cased hole.In an open-hole wellbore, a tubing string is placed into the wellbore.The tubing string allows fluids to be introduced into or flowed from aremote portion of the wellbore. In a cased hole, a casing is placed intothe wellbore that can contain a tubing string. In an open hole, thespace between the wellbore and the outside of a tubing string is anannulus. In a cased hole, the space between the wellbore and the outsideof the casing is an annulus. Also, in a cased hole, there may be anannulus between the tubing string and the inside of the casing.

As used herein, a “cement composition” is a mixture of at least cementand water, and the cement composition can include additives. As usedherein, the term “cement” means a dry powder substance that acts as abinder to bind other materials together.

During well completion, it is common to introduce a cement compositioninto an annulus in the wellbore. For example, in a cased hole, thecement composition is placed and allowed to set in the annulus betweenthe wellbore and the casing in order to stabilize and secure the casingin the wellbore. By cementing the casing in the wellbore, fluids areprevented from flowing into the annulus. Consequently, oil or gas can beproduced in a controlled manner by directing the flow of oil or gasthrough the casing and into the wellhead. Cement compositions also canbe used in well-plugging operations or gravel-packing operations.

During cementing operations, it is necessary for the cement compositionto remain pumpable during introduction into the well and until thecomposition is situated in the portion of the well to be cemented. Afterthe cement composition has reached the portion of the well to becemented, the cement composition ultimately sets. A cement compositionthat thickens too quickly while being pumped can damage pumpingequipment or block tubing or pipes, and a cement composition that setstoo slowly can cost time and money while waiting for the composition toset.

As used herein, the “thickening time” is how long it takes for a cementcomposition to become unpumpable under specified temperature andpressure conditions. The pumpability of a cement composition is relatedto the consistency of the composition. The consistency of a cementcomposition is measured in Bearden units of consistency (Be), adimensionless unit with no direct conversion factor to the more commonunits of viscosity. As used herein, a cement composition becomes“unpumpable” when the consistency of the composition reaches 70 Bc.

If any test (e.g., thickening time or shear strength) requires the stepof mixing, then the grouting composition is “mixed” according to thefollowing procedure. The water of the cement composition is added to amixing container and the container is then placed on a mixer base. Themotor of the base is then turned on and maintained at 4,000 revolutionsper minute (rpm). The cement and any other ingredients are added to thecontainer at a uniform rate in not more than 15 seconds (s). After allthe cement and any other ingredients have been added to the water in thecontainer, a cover is then placed on the container, and the cementcomposition is mixed at 12,000 rpm (+/−500 rpm) for 35 s (+/−1 s). Itshould be understood that the ingredients of a cement composition aremixed at ambient conditions (about 71° F. and about 1 atmospherepressure).

It is also to be understood that if any test (e.g., thickening time andshear strength) specifies “at” a specific temperature and possibly aspecific pressure, then the temperature and pressure of the cementcomposition is ramped up to the specified temperature and pressure afterbeing mixed at ambient temperature and pressure. For example, the cementcomposition can be mixed at 71° F. and then placed into the testingapparatus and the temperature of the cement composition can be ramped upto the specified temperature. As used herein, the rate of ramping up thetemperature is in the range of about 3° F./min to about 5° F./min. Afterthe cement composition is ramped up to the specified temperature andpossibly pressure, the cement composition is maintained at the specifiedtemperature and pressure for the duration of the testing. Theseincreases are achieved at practical rates. Pressurizing can bepractically accomplished much more quickly than heating; thus, thecement composition is pressurized much more quickly than it is heated.

As used herein, the consistency of a cement composition is measured asfollows. The cement composition is mixed. The cement composition is thenplaced in the test cell of a High-Temperature, High-Pressure (HTHP)consistometer, such as a Fann Model 275 or a Chandler Model 8240. Thecement composition is tested in the HTHP consistometer at the specifiedtemperature and specified pressure. Consistency measurements are takencontinuously until the cement composition exceeds 70 Bc.

A cement composition can develop compressive strength. Cementcomposition compressive strengths can vary from 0 psi to over 10,000psi. As used herein, compressive strength is measured at a specifiedtime after the composition has been mixed at the specified temperatureand pressure. For example, compressive strength can be measured at atime in the range of about 24 to about 48 hours after the composition ismixed at a temperature of 217° F. Compressive strength can be measuredby either a destructive method or non-destructive method.

The destructive method mechanically tests the compressive strength of acement composition sample at a specified time after mixing using acompression-testing machine. The sample is subjected to increasingpressure until it crushes. According to the destructive method, thecompressive strength is calculated from the failure load divided by thesmallest cross-sectional area in contact with the load-bearing plates ofthe compression-testing machine resisting the load. The compressivestrength is reported in units of pressure, such as pound-force persquare inch (psi) or megapascals (MPa).

The non-destructive method continually measures a correlated compressivestrength of a cement composition sample throughout the test period byutilizing a non-destructive sonic device such as an Ultrasonic CementAnalyzer (UCA) available from Farm Instruments in Houston, Tex. As usedherein, the “compressive strength” of a cement composition is measuredutilizing an Ultrasonic Cement Analyzer as follows. The cementcomposition is mixed. The cement composition is placed in an UltrasonicCement Analyzer at the specified temperature and pressure. The UCAcontinually measures the transit time of the acoustic signal through thesample. The UCA contains preset algorithms that correlate transit timeto compressive strength. The UCA reports the compressive strength of thecement composition in units of pressure, such as psi or MPa.

The compressive strength of a cement composition can be used to indicatewhen the cement composition has initially set and when it has set.

As used herein, a cement composition is considered “initially set” whenthe cement composition has developed a compressive strength of 50 psiusing the non-destructive compressive strength method at a temperatureof 217° F. and a pressure of 3,000 psi. As used herein, the “initialsetting time” is the difference in time between when the cement is addedto the water and when the composition is initially set.

As used herein, a cement composition is considered to be “set” when thecement composition becomes hard or solid. A cement composition becomesset through the process of curing. It may take up to 24 hours or longerfor a cement composition to set. Some cement compositions can continueto develop a compressive strength over the course of several days. Somecement compositions can develop a compressive strength of over 10,000psi.

A set retarder can be added to a cement composition to help increase thethickening time of the cement composition such that the cementcomposition remains pumpable for a desired time. The thickening time isproportional to the setting time, i.e., the longer the thickening time,the longer the setting time will be. Therefore, a set retarder can beadded to a cement composition to help increase the setting time of thecement composition. However, if a set retarder is in too high aconcentration, the cement composition may never set. Therefore, the setretarder also can be used in a concentration such that the cementcomposition sets in a desired time.

Conventional polymeric set retarders have been used to delay the settingtime of cement compositions. Examples of conventional set retarders aredisclosed in U.S. Pat. No. 7,004,256 issued Feb. 28, 2006 to Chatterjiet al., which is incorporated by reference in its entirety. Anotherexample of a conventional set retarder is a copolymer formed from amonomer of 2-acrylamido-2-methylpropane sulfonic acid (“AMPS”). Oneexample of a conventional AMPS set retarder is “SCR-100™”, availablefrom Halliburton Energy Services, Inc. in Duncan, Okla.

A polymer is a large molecule composed of repeating units typicallyconnected by covalent chemical bonds. The number of repeating units of apolymer can range from approximately 4 to greater than 10,000. Thenumber of repeating units of a polymer is referred to as the chainlength of the polymer. A polymer is formed from the polymerizationreaction of monomers. A polymer formed from one type of monomer iscalled a homopolymer. A copolymer is formed from two or more differenttype monomers. In the polymerization reaction, the monomers aretransformed into the repeating units of a polymer. The conditions of thepolymerization reaction can be adjusted to help control the averagenumber of repeating units (the average chain length) of a polymer. Apolymer also has an average molecular weight, which is directly relatedto the average chain length of the polymer. The average molecular weightof a polymer has an impact on some of the physical characteristics of apolymer, for example, its solubility in water and its biodegradability.

For a copolymer, each of the monomers will be repeated a certain numberof times (number of repeating units). The average molecular weight for acopolymer can be expressed as follows:

Avg. molecular weight=(M.W.m₁*RU m₁)+(M.W.m₂*RU m₂)

where M.W.m₁ is the molecular weight of the first monomer; RU m₁ is thenumber of repeating units of the first monomer; M.W.m₂ is the molecularweight of the second monomer; and RU m₂ is the number of repeating unitsof the second monomer. Of course, a terpolymer would include threemonomers, a tetra polymer would include four monomers, and so on.

It should also be understood that, as used herein, “first,” “second,”and “third,” are assigned arbitrarily and are merely intended todifferentiate between two or more monomers, fluids, etc., as the casemay be, and does not indicate any sequence. Furthermore, it is to beunderstood that the mere use of the term “first” does not require thatthere be any “second,” and the mere use of the word “second” does notrequire that there be any “third,” etc.

In a copolymer, the repeating units for each of the monomers can bearranged in various ways along the polymer chain. For example, therepeating units can be random, alternating, periodic, or block.

For a copolymer made from two monomers, the mole ratio is the ratio ofthe moles of the first monomer to the moles of the second monomer. Forexample, a copolymer can have a mole ratio of 50:50, which means that,for every one mole of the first monomer, there is one mole of the secondmonomer. By way of another example, a mole ratio of 80:20 means that,for every 4 moles of the first monomer, there is one mole of the secondmonomer. However, for a random copolymer, the mole ratio of the monomersis not as important as it would be for a block copolymer.

Some conventional polymeric set retarders do not increase the thickeningtime to at least 2 hours in high-temperature wells. As used herein, ahigh-temperature well is a well with a bottomhole temperature in therange of 150° F. to 500° F. As used herein, the bottomhole temperaturerefers to the downhole temperature at the portion of the well to becemented. In order to make some conventional polymeric set retardersincrease the thickening time to at least 2 hours in high-temperaturewells, the molecular weight of the polymer can be increased (usually toa molecular weight of greater than 10,000).

Some nations have implemented new environmental regulations which setstandards for the biodegradability of wellbore fluids (especially foroff-shore drilling). Biodegradability is the process by which complexmolecules are broken down by microorganisms to produce simplercompounds. However, as the molecular weight of a polymer increases, itsbiodegradability tends to decrease. Thus, in most of the cases, highmolecular weight polymers may not satisfy the new environmentalregulations, and, thus, the polymers may not be able to be used. As usedherein, a high molecular weight polymer is a polymer that has an averagemolecular weight of greater than 10,000. As used herein, a low molecularweight polymer is a polymer that has an average molecular weight of lessthan 10,000.

Also, in general, as the molecular weight of a polymer increases, itssolubility decreases. As a result, some high molecular weight polymersare generally water-swellable; whereas, some low molecular weightpolymers are generally water soluble. As used herein, a polymer is“water soluble” if at least 1 part by weight of the polymer dissolves in5 parts by weight of deionized water at a temperature of 80° F.

As used herein, a polymer is considered “biodegradable” if the polymerpasses a ready biodegradability test or an inherent biodegradabilitytest. It is preferred that a polymer is first tested for readybiodegradability, and only if the polymer does not pass at least one ofthe ready biodegradability tests then the polymer is tested for inherentbiodegradability. It is believed that the polymer according to theinvention will pass the ready biodegradability test and will not need tobe tested for inherent biodegradability.

In accordance with Organisation for Economic Co-operation andDevelopment (OECD) guidelines, the following six tests permit thescreening of chemicals for ready biodegradability. As used herein, apolymer showing more than 60% biodegradability in 28 days according toany one of the six ready biodegradability tests is considered a passlevel for classifying it as “readily biodegradable,” and it may beassumed that the polymer will undergo rapid and ultimate degradation inthe environment. The six ready biodegradability tests are: (1) 301 A:DOC Die-Away; (2) 301 B: CO2 Evolution (Modified Sturm Test); (3) 301 C:MITI (I) (Ministry of International Trade and Industry, Japan); (4) 301D: Closed Bottle; (5) 301 E: Modified OECD Screening; and (6) 301 F:Manometric Respirometry. The six ready biodegradability tests aredescribed below:

(1) For the 301A test, a measured volume of inoculated mineral medium,containing 10 mg to 40 mg dissolved organic carbon per liter (DOC/1)from the polymer as the nominal sole source of organic carbon, isaerated in the dark or diffuse light at 22±2° C. Degradation is followedby DOC analysis at frequent intervals over a 28-day period. The degreeof biodegradation is calculated by expressing the concentration of DOCremoved (corrected for that in the blank inoculum control) as apercentage of the concentration initially present. Primarybiodegradation may also be calculated from supplemental chemicalanalysis for parent compound made at the beginning and end ofincubation.

(2) For the 301B test, a measured volume of inoculated mineral medium,containing 10 mg to 20 mg DOC or total organic carbon per liter from thepolymer as the nominal sole source of organic carbon is aerated by thepassage of carbon dioxide-free air at a controlled rate in the dark orin diffuse light. Degradation is followed over 28 days by determiningthe carbon dioxide produced. The CO₂ is trapped in barium or sodiumhydroxide and is measured by titration of the residual hydroxide or asinorganic carbon. The amount of carbon dioxide produced from the testsubstance (corrected for that derived from the blank inoculum) isexpressed as a percentage of ThCO₂. The degree of biodegradation mayalso be calculated from supplemental DOC analysis made at the beginningand end of incubation.

(3) For the 301C test, the oxygen uptake by a stirred solution, orsuspension, of the polymer in a mineral medium, inoculated withspecially grown, unadapted micro-organisms, is measured automaticallyover a period of 28 days in a darkened, enclosed respirometer at 25+/−1°C. Evolved carbon dioxide is absorbed by soda lime. Biodegradation isexpressed as the percentage oxygen uptake (corrected for blank uptake)of the theoretical uptake (ThOD). The percentage primary biodegradationis also calculated from supplemental specific chemical analysis made atthe beginning and end of incubation, and optionally ultimatebiodegradation by DOC analysis.

(4) For the 301D test, a solution of the polymer in mineral medium,usually at 2-5 milligrams per liter (mg/l), is inoculated with arelatively small number of micro-organisms from a mixed population andkept in completely full, closed bottles in the dark at constanttemperature. Degradation is followed by analysis of dissolved oxygenover a 28 day period. The amount of oxygen taken up by the microbialpopulation during biodegradation of the test substance, corrected foruptake by the blank inoculum run in parallel, is expressed as apercentage of ThOD or, less satisfactorily COD.

(5) For the 301E test, a measured volume of mineral medium containing 10to 40 mg DOC/l of the polymer as the nominal sole source of organiccarbon is inoculated with 0.5 ml effluent per liter of medium. Themixture is aerated in the dark or diffused light at 22+2° C. Degradationis followed by DOC analysis at frequent intervals over a 28 day period.The degree of biodegradation is calculated by expressing theconcentration of DOC removed (corrected for that in the blank inoculumscontrol) as a percentage of the concentration initially present. Primarybiodegradation may also be calculated from supplemental chemicalanalysis for the parent compound made at the beginning and end ofincubation.

(6) For the 301F test, a measured volume of inoculated mineral medium,containing 100 mg of the polymer per liter giving at least 50 to 100 mgThOD/l as the nominal sole source of organic carbon, is stirred in aclosed flask at a constant temperature (+1° C. or closer) for up to 28days. The consumption of oxygen is determined either by measuring thequantity of oxygen (produced electrolytically) required to maintainconstant gas volume in the respirometer flask or from the change involume or pressure (or a combination of the two) in the apparatus.Evolved carbon dioxide is absorbed in a solution of potassium hydroxideor another suitable absorbent. The amount of oxygen taken up by themicrobial population during biodegradation of the test substance(corrected for uptake by blank inoculum, run in parallel) is expressedas a percentage of ThOD or, less satisfactorily, COD. Optionally,primary biodegradation may also be calculated from supplemental specificchemical analysis made at the beginning and end of incubation, andultimate biodegradation by DOC analysis.

In accordance with OECD guidelines, the following three tests permit thetesting of chemicals for inherent biodegradability. As used herein, apolymer with a biodegradation or biodegradation rate of >20% is regardedas “inherently primary biodegradable.” A polymer with a biodegradationor biodegradation rate of >70% is regarded as “inherently ultimatebiodegradable.” As used herein, a polymer passes the inherentbiodegradability test if the polymer is either regarded as inherentlyprimary biodegradable or inherently ultimate biodegradable when testedaccording to any one of three inherent biodegradability tests. The threetests are: (1) 302 A-1981 Modified SCAS Test; (2) 302 B-1992Zahn-Wellens Test; and (3) 302 C-1981 Modified MITI Test. Inherentbiodegradability refers to tests which allow prolonged exposure of thetest compound to microorganisms, a more favorable test compound tobiomass ratio, and chemical or other conditions which favorbiodegradation. The three inherent biodegradability tests are describedbelow:

(1) For the 302A test, activated sludge from a sewage treatment plant isplaced in an aeration (SCAS) unit. The polymer and settled domesticsewage are added, and the mixture is aerated for 23 hours. The aerationis then stopped, the sludge allowed to settle and the supernatant liquoris removed. The sludge remaining in the aeration chamber is then mixedwith a further aliquot of the polymer and sewage and the cycle isrepeated. Biodegradation is established by determination of thedissolved organic carbon content of the supernatant liquor. This valueis compared with that found for the liquor obtained from a control tubedosed with settled sewage only.

(2) For the 302B test, a mixture containing the polymer, mineralnutrients, and a relatively large amount of activated sludge in aqueousmedium is agitated and aerated at 20° C. to 25° C. in the dark or indiffuse light for up to 28 days. A blank control, containing activatedsludge and mineral nutrients but no polymer, is run in parallel. Thebiodegradation process is monitored by determination of DOC (or COD(2))in filtered samples taken at daily or other time intervals. The ratio ofeliminated DOC (or COD), corrected for the blank, after each timeinterval, to the initial DOC value is expressed as the percentagebiodegradation at the sampling time. The percentage biodegradation isplotted against time to give the biodegradation curve.

(3) For the 302C test, an automated closed-system oxygen consumptionmeasuring apparatus (BOD-meter) is used. The polymer to be tested isinoculated in the testing vessels with micro-organisms. During the testperiod, the biochemical oxygen demand is measured continuously by meansof a BOD-meter. Biodegradability is calculated on the basis of BOD andsupplemental chemical analysis, such as measurement of the dissolvedorganic carbon concentration, concentration of residual chemicals, etc.

It has been discovered that a water-soluble, biodegradable homopolymerof epoxysuccinic acid can be used as a set retarder. Another advantageaccording to the invention is that a water-soluble, biodegradablehomopolymer of epoxysuccinic acid is a green scale inhibitor and isbiocompatible. As used herein, “biocompatible” means the quality of nothaving toxic or injurious effects on biological systems. For example, ifa cement composition including a homopolymer of epoxysuccinic acid wereused in off-shore drilling, then a release of the polymer into the waterwould not be harmful to aquatic life. Yet another advantage to thepolymer is it is salt tolerant. As used herein, “salt tolerant” meansthat a cement composition containing 325 g of deionized water, 860 g ofClass-H Portland Cement, 0.4% bwc of the polymer, and sodium chloride(NaCl) at a concentration of 30% by weight of the water (bww), at atemperature of 125° F. and a pressure of 5,160 psi, will have athickening time of at least 2 hours. Thus, it is believed that a polymercomprising a monomer or monomers selected from the group consisting ofepoxysuccinic acid, a substituted epoxysuccinic acid, and an alkalimetal salt, alkaline earth metal salt, or ammonium salt of any of theforegoing, and any combination of any of the foregoing can be watersoluble and biodegradable, and, in addition, can be a green scaleinhibitor and biocompatible, can be used in the presence of salt, andcan be more cost effective compared to conventional set retarders.

According to an embodiment, a cement composition for use in asubterranean formation is provided. The cement composition comprises:(A) cement; (B) water; and (C) a polymer, wherein the polymer: (i)comprises a monomer or monomers selected from the group consisting ofepoxysuccinic acid, a substituted epoxysuccinic acid, and an alkalimetal salt, alkaline earth metal salt, or ammonium salt of any of theforegoing, and any combination of any of the foregoing; (ii) has thefollowing characteristics: (a) is water soluble; and (b) isbiodegradable; and (iii) is capable of providing: (a) a thickening timeof at least 2 hours for a test composition at a temperature of 190° F.and a pressure of 5,160 psi; and (b) an initial setting time of lessthan 24 hours for the test composition at a temperature of 217° F. and apressure of 3,000 psi, wherein the test composition consists of 860grams of Class-H Portland cement, 325 grams of deionized water, and 0.4%by weight of the cement of the polymer.

According to another embodiment, a method for cementing in asubterranean formation is provided. The method comprises the steps of:(A) introducing the cement composition into the subterranean formation;and (B) allowing the cement composition to set after introduction intothe subterranean formation.

The cement composition includes cement. The cement can be a Portlandcement, a pozzalonic cement, a gypsum cement, a high alumina contentcement, a silica cement, and any combination thereof. Preferably, thecement is Portland Cement Type I, II, or III. Preferably, the cement isClass A cement, Class C cement, Class G cement, or Class H cement.Preferably, the cement composition has a density in the range of about 9to about 22 pounds per gallon (ppg).

The cement composition includes water. The water can be selected fromthe group consisting of freshwater, brackish water, and saltwater, inany combination thereof in any proportion. The cement composition alsocan include salt. Preferably, the salt is selected from sodium chloride,calcium chloride, calcium bromide, potassium chloride, potassiumbromide, magnesium chloride, and any combination thereof in anyproportion. Preferably, the salt is in a concentration in the range ofabout 0.1% to about 40% by weight of the water.

The cement composition includes a polymer, wherein the polymer comprisesa monomer or monomers selected from the group consisting ofepoxysuccinic acid, a substituted epoxysuccinic acid, and an alkalimetal salt, alkaline earth metal salt, or ammonium salt of any of theforegoing, and any combination of any of the foregoing in anyproportion. Preferably, any of the other monomers that may be present inthe polymer are not AMPS or lignosulfonate and its salts.

Preferably, the polymer consists essentially of a monomer or monomersselected from the group consisting of epoxysuccinic acid, a substitutedepoxysuccinic acid, and an alkali metal salt, alkaline earth metal salt,or ammonium salt of any of the foregoing, and any combination of any ofthe foregoing. The polymer can contain other monomers so long as thepresence of the other monomers does not materially affect the basic andnovel characteristics of the claimed invention.

The polymer can be an alkali metal salt, an alkaline earth metal salt,or an ammonium salt. The monomer(s) can be neutralized prior to thepolymerization reaction. The polymer can be neutralized or at leastpartially neutralized after the polymerization reaction. An example ofsuch an alkali metal salt is sodium polyepoxysuccinate. An example ofsuch an alkaline earth metal salt is calcium polyepoxysuccinate. Anexample of such an ammonium salt is ammonium polyepoxysuccinate.

The polymer can be a homopolymer having the following structuralformula:

where M=hydrogen (H⁺), sodium (Na⁺), potassium (K⁺), or ammonium (NH₄ ⁺)and where R=hydrogen or a hydrocarbyl of 1 to 4 carbons (C1-4). M1 andM2 can be the same or different, for example, M1 can be H⁺ and M2 can beK⁺. Also, R1 and R2 can be the same or different. Preferably thehydrocarbyl is an aliphatic group such as methyl, ethyl, propyl, butyl,isopropyl, etc. Preferably, the polymer has an average chain length (n)in the range of 3 to 60. More preferably, the polymer has an averagechain length (n) of 3 to 30.

The polymer can be, for example, a homopolymer of epoxysuccinic acid(ESA) or a homopolymer of a substituted ESA. Referring to the structuralformula above, a homopolymer of ESA is where both M1 and M2=H⁺ and bothR1 and R2=H. A homopolymer of a substituted ESA is where both M1 andM2=H⁺ and where at least one of the R1 and R2=a hydrocarbyl of 1 to 4carbons.

The polymer can be a homopolymer formed from monomers selected from analkali metal salt of ESA, an alkaline earth metal salt of ESA, and anammonium salt of ESA, in which both R1 and R2=H. By way of example, ahomopolymer formed from an ammonium salt of ESA is where at least one ofM1 and M2=NH₄ ⁺. As mentioned elsewhere herein, it should be understoodthat a homopolymer of ESA can be at least partially neutralized afterthe polymerization, for example neutralized with ammonia to form an atleast partially neutralized ammonium salt of polyepoxysuccinic acid.

The polymer can be a homopolymer formed from monomers selected from analkali metal salt of a substituted ESA, an alkaline earth metal salt ofa substituted ESA, and an ammonium salt of a substituted ESA, in whichat least one of R1 and R2 is a hydrocarbyl of 1 to 4 carbons. By way ofexample, a homopolymer formed from an ammonium salt of a substituted ESAis where at least one of M1 and M2=NH₄ ⁺ and at least one of R1 andR2=C1-4.

Most preferably, the homopolymer is polyepoxysuccinic acid.

The polymer can be a copolymer formed from two or more differentmonomers selected from ESA, a substituted ESA, and an alkali metal salt,alkaline earth metal salt, and an ammonium salt of any of the foregoing.By way of example, the polymer can be a copolymer formed from two ormore different monomers selected from substituted ESAs. For example, thefirst substituted ESA monomer can have R1=C1; whereas, the secondsubstituted ESA monomer can have R1=C3. Preferably, if the polymer is acopolymer, then the repeating units are random.

Among other things, the polymer has an average molecular weight suchthat the polymer has the following characteristics: it is water soluble;it is biodegradable; and it provides the desired thickening time andinitial setting time to the cement composition. Preferably, the polymerhas an average molecular weight in the range of about 400 to about8,000. More preferably, the polymer has an average molecular weight inthe range of about 400 to about 4,000. Most preferably, the polymer hasan average molecular weight in the range of about 400 to about 1,500.

Preferably, the polymer is in at least a sufficient concentration suchthat the cement composition has a thickening time of at least 3 hours ata temperature of 217° F. and a pressure of 10,200 psi, whereas anotherwise identical cement composition without the polymer would have athickening time of less than 3 hours at the same temperature andpressure. Preferably, the polymer is in a concentration equal to or lessthan a sufficient concentration such that the cement composition sets inless than 48 hours at a temperature of 217° F. and a pressure of 3,000psi. Preferably, the polymer is in a concentration in the range of about0.01% to about 10% by weight of the cement (bwc). More preferably, thepolymer is in a concentration in the range of about 0.02% to about 2%bwc. One of skill in the art will be able to determine the concentrationof the polymer needed in order to achieve the desired thickening time,for example, based on the amount of salt which may be present in thewater and the bottomhole temperature of the well, among other specificconditions of the well.

Preferably, the cement composition has a thickening time in the range ofabout 3 to about 10 hours at a temperature of 217° F. and a pressure of10,200 psi. More preferably, the cement composition has a thickeningtime in the range of about 4 to about 7 hours at a temperature of 217°F. and a pressure of 10,200 psi. Some of the variables that can affectthe thickening time of the cement composition include the concentrationof the polymer, the concentration of any salt present in the cementcomposition, and the bottomhole temperature of the well. Preferably, thecement composition sets in less than 48 hours at a temperature of 217°F. and a pressure of 3,000 psi. More preferably, the cement compositionsets in less than 24 hours at a temperature of 217° F. and a pressure of3,000 psi. Most preferably, the cement composition sets at a time in therange of about 8 to about 24 hours at a temperature of 217° F. and apressure of 3,000 psi.

Preferably, the cement composition has a compressive strength of atleast 500 psi when tested at 24 hours at a temperature of 217° F. and apressure of 3,000 psi. More preferably, the cement composition has acompressive strength in the range of about 500 to about 10,000 psi whentested at 24 hours at a temperature of 217° F. and a pressure of 3,000psi.

The cement composition can also include at least one additional setretarder to help control the thickening time of the cement composition.Preferably, any additional set retarder is also biodegradable.

The cement composition can include at least one additive suitable foruse in subterranean cementing operations. Examples of such additivesinclude, but are not limited to, a strength-retrogression additive, aset accelerator, a set retarder, a weighting agent, a lightweightadditive, a gas-generating additive, a mechanical property enhancingadditive, a lost-circulation material, a filtration-control additive, adispersant, a fluid loss control additive, a defoaming agent, a foamingagent, a thixotropic additive, a nano-particle, and combinationsthereof. Preferably, any other additives are also biodegradable. Forexample, the cement composition can include a strength-retrogressionadditive. The strength-retrogression additive can be selected from thegroup consisting of course silica flour, fine silica flour, and anycombination thereof in any proportion. Preferably, the strengthstabilizer is in a concentration in the range of about 20% to about 50%by weight of the cement.

The cement composition can include a fluid loss additive. Suitableexamples of fluid loss additives include HALAD®344, HALAD®413,HALAD®400, HALAD®9, HALAD®14, HALAD®23, HALAD®100A, HALAD®300,HALAD®350, HALAD®400L, HALAD®600, HALAD®600LE+, HALAD®613, HALAD®766,FDP-703, Latex 2000, LAP-1, and LA-2, available from Halliburton EnergyServices, Inc. Preferably, the fluid loss additive is in a concentrationin the range of 0.1% to 4% by weight of the cement. The fluid lossadditive is preferably biodegradable. Examples of suitable biodegradablefluid loss additives include HALAD®400 and HALAD®300.

The cement composition can include a dispersant. Suitable examples ofdispersants include CFR®2, CFR®3, CFR®5LE, CFR®6, CFR®8, FDP-701, andFDP-C-850, available from Halliburton Energy Services, Inc. Preferably,the dispersant is in a concentration in the range of 0.05% to 3% byweight of the cement.

The cement composition also can include a filler material. Suitableexamples of filler materials include, but are not limited to, fly ash,sand, clays, and vitrified shale. Preferably, the filler material is ina concentration in the range of about 5% to about 50% by weight of thecement.

The cement composition also can include other additives.Commercially-available examples of other additives include, but are notlimited to, SSA-1, SSA-2, High Dense-3, High Dense-4, Barite, Micromax,Silicalite, HGS-6000, HGS-4000, HGS-10000, Well life 665, Well life 809,and Well life 810, available from Halliburton Energy Services, Inc.

The method includes the step of introducing the cement composition intoa subterranean formation. Preferably, the subterranean formation ispenetrated by a well and the step of introducing is into a portion ofthe well. Preferably, the portion of the well is a portion of anannulus. The step of introducing can be for the purpose of wellcompletion, primary or remedial cementing operations, squeeze cementing,well-plugging, or gravel packing. The cement composition is in apumpable state upon introduction into the subterranean formation. Themethod also includes the step of allowing the cement composition to setafter introduction into the subterranean formation. The method caninclude the additional steps of perforating, fracturing, or performingan acidizing treatment, after the step of allowing the cementcomposition to set.

If the step of introducing is into a portion of a well, then preferably,the cement composition has a thickening time of at least 3 hours at thebottomhole temperature and pressure of the well. More preferably, thecement composition has a thickening time in the range of about 4 toabout 10 hours at the bottomhole temperature and pressure of the well.For example, one of skill in the art will be able to select thethickening time based on the specific conditions of the well (e.g., thelength of the casing and the bottomhole temperature of the well). Someof the variables that can affect the thickening time of the cementcomposition include the concentration of the polymer, the concentrationof any salt present in the cement composition, and the bottomholetemperature of the well. Preferably, the cement composition sets in lessthan 48 hours at the bottomhole temperature and pressure of the well.More preferably, the cement composition sets in less than 24 hours atthe bottomhole temperature and pressure of the well. Most preferably,the cement composition sets at a time in the range of about 8 to about24 hours at the bottomhole temperature and pressure of the well.Preferably, the cement composition is used in a well having a bottomholetemperature of at least 150° F. Preferably, the bottomhole temperatureis in the range of about 150° F. to about 500° F. More preferably, thebottomhole temperature is in the range of about 180° F. to about 400° F.Most preferably, the bottomhole temperature is in the range of about180° F. to about 350° F. Preferably, the cement composition develops acompressive strength of at least 1,500 psi after the cement compositionhas been introduced into the well and is situated in the portion of wellto be cemented.

EXAMPLES

To facilitate a better understanding of the present invention, thefollowing examples of certain embodiments are given. The followingexamples are not the only examples that could be given according to thepresent invention and are not intended to limit the scope of theinvention.

Table 1 and FIGS. 1, 2, and 3 show the effect of the concentration of apolymer or temperature of the cement composition on thickening time. ForTable 1 and FIGS. 1, 2, and 3 several cement compositions, having adensity of 16.4 pounds per gallon (ppg), were prepared. The cementcompositions consisted of 5.48 gallons of deionized water; Class-Hcement; SSA-2™ strength stabilizer at a concentration of 35% by weightof the cement (bwc); HALAD®344 fluid loss additive at a concentration of0.5% bwc; and a set retarder. Table 1 shows the thickening time for thecement compositions at a pressure of 10,200 psi, wherein the setretarder is either SCR-100™ (a conventional polymeric set retarder) orpolyepoxysuccinic acid (“PESA”) having an average molecular weight inthe range of 400-1,500. FIG. 1 is a graph of thickening time versustemperature for the cement composition at a pressure of 10,200 psi withPESA at a concentration of 0.4% bwc. FIG. 2 is a graph of thickeningtime versus concentration of PESA for the cement composition at atemperature of 217° F. and a pressure of 10,200 psi. FIG. 3 is a graphof temperature (° F.) and consistency (Bc) versus time (hr:min) for thecement composition at a pressure of 10,200 psi with PESA at aconcentration of 0.4% bwc. For Table 1, the cement compositions wereheated from an initial temperature of 70° F. to a maximum temperature ofat least 140° F. over the course of 44 minutes and then maintained atthat maximum temperature. The thickening time is the time it took forthe cement compositions to reach 70 Bc. The consistency of the cementcompositions was measured using a Fann Model 275 HTHP consistometer. Theinitial setting time of the cement compositions was the time it took forthe cement compositions to reach 50 psi, at a pressure of 3,000 psi,using an Ultrasonic Cement Analyzer.

TABLE 1 Initial Cement Concentration Thickening Setting Set of RetarderTemperature Time Time Retarder (% bwc) (° F.) (hr:min) (hr:min) 1SCR-100 0.4 217 4-6 11:24 2 PESA 0.05 140 4:09 Not measured 3 PESA 0.1190 4:34 Not measured 4 PESA 0.4 190 19:50  Not measured 5 PESA 0.2 2173:40 09:33 6 PESA 0.4 217 8:06 14:34 7 PESA 0.6 217 9:33 Not measured 8PESA 0.4 245 3:17 Not measured 9 PESA 0.8 280 2:15 Not measured 10 PESA1.5 280 6:02 Not measured

As can be seen in Table 1 and FIG. 1, for a fixed concentration of PESA,the thickening time decreases with an increase in temperature. As canalso be seen in Table 1, PESA performs comparably to the conventionalpolymeric set retarder SCR-100™. As can be seen in Table 1 and FIG. 2,for a fixed temperature, the thickening time increases with an increasein concentration of PESA. As can be seen in FIG. 3, it tookapproximately 3 hours for the cement composition to reach approximately100 Bc at a temperature of approximately 245° F.

Table 2 and FIG. 4 show the effect of salt in the cement composition onthickening time. For Table 2 several 16.4 ppg cement compositions wereprepared containing 5.48 gallons of deionized water, seawater, orsaltwater having varying concentrations of salt; Class-H cement; SSA-2™strength stabilizer at a concentration of 35% bwc; HALAD®344 fluid lossadditive at a concentration of 0.5% bwc; and PESA at a concentration of0.4% bwc. For Table 2, the cement compositions were heated from aninitial temperature of 70° F. to a maximum temperature of 217° F. overthe course of 44 minutes and then maintained at 217° F. and a pressureof 10,200 psi. The thickening time is the time it took for the cementcompositions to reach 70 Bc. The consistency of the cement compositionswas measured using a Fann Model 275 HTHP consistometer. For FIG. 4, a16.4 ppg cement composition was prepared containing 5.48 gallons ofwater; sodium chloride (NaCl) at a concentration of 35% by weight of thewater (bww); Class-H cement; SSA-2™ strength stabilizer at aconcentration of 35% bwc; HALAD®344 fluid loss additive at aconcentration of 0.5% bwc; and PESA at a concentration of 0.4% bwc. FIG.4 is a graph of temperature (° F.) and consistency (Be) versus time(hr:min) for the cement composition maintained at 10,200 psi.

TABLE 2 Concentration Tem- Cement of Set Concentration per- ThickeningSet Retarder of ature Time Retarder (% bwc) NaCl (% bww) (° F.) (hr:min)1 PESA 0.4 Not Present 217 8:06 2 PESA 0.4 Sea Water 217 6:19 3 PESA 0.410 217 6:43 4 PESA 0.4 35 217 16:27 

As can be seen in Table 2, NaCl acts as an accelerator for the cementcomposition when the concentration of the salt is ≦15% bww. But NaClshows a retarding effect when the concentration of NaCl is in the rangeof 20-35% bww. For that reason, the thickening time of slurry 2 and 3decreases compared to slurry 1 and the thickening time of slurry 4increases compared to slurry 1. As can be seen in FIG. 4, it tookapproximately 16 hours for the cement composition to reach approximately100 Bc at a temperature of approximately 215° F.

Table 3 shows the rheology of various cement compositions. For Table 3several 16.4 ppg cement compositions were prepared containing 5.48gallons of deionized water; Class-H cement; SSA-2™ strength stabilizerat a concentration of 35% bwc; HALAD®344 fluid loss additive at aconcentration of 0.5% bwc; and varying concentrations of PESA. Therheology of the cement compositions were measured using a FANN 35viscometer with a standard Bob and Sleeve attachment and Spring number 1at a temperature of 70° F. and a dial reading of 3 to 600 revolutionsper minute (rpm).

TABLE 3 PESA Concentration Revolutions per minute (rpm) (% bwc) 3 6 3060 100 200 300 600 0.2 3 5 16 29 41 78 109 185 0.4 9 11 21 42 58 96 137233 0.6 9 11 25 38 53 85 120 208

As can be seen in Table 3, the cement compositions containing PESAexhibit acceptable rheology across a wide concentration range. Littlevariation in dial reading has been found with an increase in PESAconcentration from 0.2% bwc to 0.4% bwc. However, a further increase inthe concentration of PESA does not affect the rheologies, which indicateits utility at high concentrations (>0.6% bwc).

Therefore, the present invention is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Furthermore, no limitations areintended to the details of construction or design herein shown, otherthan as described in the claims below. It is, therefore, evident thatthe particular illustrative embodiments disclosed above may be alteredor modified and all such variations are considered within the scope andspirit of the present invention. While compositions and methods aredescribed in terms of “comprising,” “containing,” or “including” variouscomponents or steps, the compositions and methods also can “consistessentially of” or “consist of” the various components and steps.Whenever a numerical range with a lower limit and an upper limit isdisclosed, any number and any included range falling within the range isspecifically disclosed. In particular, every range of values (of theform, “from about a to about b,” or, equivalently, “from approximately ato b,” or, equivalently, “from approximately a to b”) disclosed hereinis to be understood to set forth every number and range encompassedwithin the broader range of values. Also, the terms in the claims havetheir plain, ordinary meaning unless otherwise explicitly and clearlydefined by the patentee. Moreover, the indefinite articles “a” or “an”,as used in the claims, are defined herein to mean one or more than oneof the element that it introduces. If there is any conflict in theusages of a word or term in this specification and one or more patent(s)or other documents that may be incorporated herein by reference, thedefinitions that are consistent with this specification should beadopted.

1. A method for cementing in a subterranean formation, the methodcomprising the steps of: (A) introducing a cement composition into thesubterranean formation, the composition comprising: (i) cement; (ii)water; and (iii) a polymer, wherein the polymer: (a) comprises a monomeror monomers selected from the group consisting of epoxysuccinic acid, asubstituted epoxysuccinic acid, and an alkali metal salt, alkaline earthmetal salt, or ammonium salt of any of the foregoing, and anycombination of any of the foregoing; (b) has the followingcharacteristics: (I) is water soluble; and (II) is biodegradable; and(c) is capable of providing: (I) a thickening time of at least 2 hoursfor a test composition at a temperature of 190° F. and a pressure of5,160 psi, and (II) an initial setting time of less than 24 hours forthe test composition at a temperature of 217° F. and a pressure of 3,000psi, wherein the test composition consists of 860 grams of Class-HPortland cement, 325 grams of deionized water, and 0.4% by weight of thecement of the polymer; and (B) allowing the cement composition to setafter introduction into the subterranean formation.
 2. The methodaccording to claim 1, wherein the polymer consists essentially of amonomer or monomers elected from the group consisting of epoxysuccinicacid, a substituted epoxysuccinic acid, and an alkali metal salt,alkaline earth metal salt, or ammonium salt of any of the foregoing, andany combination of any of the foregoing.
 3. The method according toclaim 1, wherein the cement is selected from the group consisting of aPortland cement, a pozzalonic cement, a gypsum cement, a high aluminacontent cement, a silica cement, and any combination thereof.
 4. Themethod according to claim 1, wherein the cement is Class A cement, ClassC cement, Class G cement, or Class H cement.
 5. The method according toclaim 1, wherein the polymer is in at least a sufficient concentrationsuch that the cement composition has a thickening time of at least 3hours at a temperature of 217° F. and a pressure of 10,200 psi, whereasan otherwise identical cement composition without the polymer would havea thickening time of less than 3 hours at the same temperature andpressure.
 6. The method according to claim 1, wherein the polymer is ina concentration equal to or less than a sufficient concentration suchthat the cement composition sets in less than 48 hours at a temperatureof 217° F. and a pressure of 3,000 psi.
 7. The method according to claim1, wherein the polymer is in a concentration in the range of about 0.01%to about 10% by weight of the cement.
 8. The method according to claim1, wherein the polymer is in a concentration in the range of about 0.02%to about 2% by weight of the cement.
 9. The method according to claim 1,wherein the polymer has an average molecular weight in the range ofabout 400 to about 8,000.
 10. The method according to claim 1, whereinthe polymer has an average molecular weight in the range of about 400 toabout 5,000.
 11. The method according to claim 1, wherein the polymerhas an average molecular weight in the range of about 400 to about1,500.
 12. The method according to claim 1, wherein the polymer is ahomopolymer and the monomer is a substituted epoxysuccinic acid.
 13. Themethod according to claim 1, wherein the polymer is a homopolymer andthe monomer is epoxysuccinic acid.
 14. The method according to claim 1,wherein the cement composition has a thickening time of at least 3 hoursat a temperature of 217° F. and a pressure of 10,200 psi.
 15. The methodaccording to claim 1, wherein the cement composition has a thickeningtime in the range of about 4 to about 10 hours at a temperature of 217°F. and a pressure of 10,200 psi.
 16. The method according to claim 1,wherein the cement composition has a compressive strength of at least500 psi when tested at 24 hours at a temperature of 217° F. and apressure of 3,000 psi.
 17. The method according to claim 1, wherein thecement composition has a compressive strength in the range of 500 to10,000 psi when tested at 24 hours at a temperature of 217° F. and apressure of 3,000 psi.
 18. The method according to claim 1, wherein thesubterranean formation is penetrated by a well and the step ofintroducing is into a portion of the well.
 19. The method according toclaim 1, wherein the well has a bottomhole temperature in the range ofabout 180° F. to about 400° F.
 20. A cement composition or use in asubterranean formation, the cement composition comprising: (A) cement;(B) water; and (C) a polymer, wherein the polymer: (i) comprises amonomer or monomers selected from the group consisting of epoxysuccinicacid, a substituted epoxysuccinic acid, and an alkali metal salt,alkaline earth metal salt, or ammonium salt of any of the foregoing, andany combination of any of the foregoing; (ii) has the followingcharacteristics: (a) is water soluble; and (b) is biodegradable; and(iii) is capable of providing: (a) a thickening time of at least 2 hoursfor a test composition at a temperature of 190° F. and a pressure of5,160 psi; and (b) an initial setting time of less than 24 hours for thetest composition at a temperature of 217° F. and a pressure of 3,000psi, wherein the test composition consists of 860 grams of Class-HPortland cement, 325 grams of deionized water, and 0.4% by weight of thecement of the polymer.
 21. The method according to claim 20, wherein thepolymer consists essentially of a monomer or monomers elected from thegroup consisting of epoxysuccinic acid, a substituted epoxysuccinicacid, and an alkali metal salt, alkaline earth metal salt, or ammoniumsalt of any of the foregoing, and any combination of any of theforegoing.